Compositions containing quaternary ammonium salts or imidazolinium compounds having at least one long chain hydrocarbyl group are commonly used to provide fabric softening benefits when used in a laundry rinse operation. Numerous patents have been issued for these types of compounds and compositions.
More recently, however, in view of concerns for the environmental safety (e.g., biodegradability) of the quaternary compound softeners, as well as limits in the amounts of these cationic compounds which can be stably incorporated into the more convenient to use liquid formulations, there have been many proposals for partial or total replacements for the conventional "quat" fabric softeners which are exemplified by dimethyl distearyl (or ditallow) ammonium chloride and various imidazolinium compounds.
For instance in GB 2,032,479A, corresponding to EP 038862, to D. Fontanesi (assigned to Albright & Wilson Ltd.) water dispersible unquaternized hydroxyalkyl diamidoamine compounds of formula EQU RNH((CH.sub.2).sub.n NR).sub.m R
wherein an average of from 20% to 80% of the R groups are C.sub.12 to C.sub.22 acyl, at least 20% of the R groups are --CH.sub.2 CH.sub.2 OH or --CH.sub.2 CHOHCH.sub.3 or mixtures of these groups, and any other R group is hydrogen, n is 2 or 3 and m is an integer of from 2 to 5, are provided as mobile pastes in the presence of lower alkanol solvents. This is stated to be in contrast to partially neutralized unquaternized diamidoamines which, while providing highly effective fabric softening properties, are too viscous even when diluted in the lower alkanol solvents for convenient handling.
U.S. Pat. No. 5,154,838 (corresponding to EP 0459211A2) to Yomamura, et al. (assigned to Kao Corp.) discloses an aqueous liquid softener composition based on an amidoamine compound which is the condensation reaction product of a di- or tri-amine of formula (I) EQU R.sup.1 NH(C.sub.m H.sub.2m NH).sub.n H (I)
with a fatty acid of formula (II) ##STR1## wherein R.sup.1 represents a straight or branched chain, saturated or unsaturated hydrocarbon group having 8 to 24 carbon atoms, R.sup.2 represents a straight or branched, saturated or unsaturated hydrocarbon group having 7 to 23 carbon atoms, m represents 2 or 3, and n is 1 or 2. These compounds, which are neither hydroxylated or ethoxylated, are noted to have high dispersibility in rinse water, especially when the amidoamine compound is used in the form of its neutral salt.
In U.S. Pat. No. 5,133,885 to L. Contor, et al. (assigned to Colgate-Palmolive Co., the assignee of the present invention) fabric softening compositions are described which are aqueous dispersions of a fatty acid ester quat of formula ##STR2## where one or two R groups represent an aliphatic ester residue of from 12 to 30 carbon atoms of formula --(CH.sub.2)--.sub.n OCOR.sub.4, and the remaining R groups represent lower aliphatic, aralkyl or hydroxyalkyl groups, X.sup.- is an anion and "a" represents the ionic valence of the anion, and a fatty acid amidoamine softener of formula ##STR3## where R.sup.1 is a C.sub.12 to C.sub.30 alkyl or alkenyl group, R.sup.2 represents R.sup.1,R.sup.1 CONH(CH.sub.2).sub.m or CH.sub.2 CH.sub.2 OH; R.sup.3 represents hydrogen, methyl or (CH.sub.2 CH.sub.2 O).sub.p H, m is a number of 1 to 5 and p is a number of 1 to 5, at a weight ratio of ester quat to amidoamine of from 10:1 to 1:10.
U.S. Pat. No. 4,772,403 to Grandmaire, et al. (Colgate-Palmolive Co.) discloses aqueous fabric softening compositions, especially adapted for use in the rinse cycle of a laundering process. These compounds are based upon (i) cationic fabric softening compounds and (ii) fatty alcohol having an alkyl group of from about 10 to about 22 carbon atoms at an (i)=(ii) weight ratio of from 6:1 to about 2.8:1, and a total amount of (i) and (ii) of 3 to 20 weight percent. A minor amount of water soluble electrolyte and/or an ethoxylated amine can be used as optional ingredients, the latter as an emulsifier to further increase the stability against phase separation of the suspended phase of the formulation.
U.S. Pat. No. 5,108,628 to Uphues, et al. (Henkel) discloses certain aliphatic carboxylic acid amidoamines which are obtained by reaction of polyamines (e.g., diethylentriamine, aminoethyl ethanolamine) with carboxylic acid mixtures containing ether carboxylic acids (R--O--(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 COOH, R=C.sub.8-18 alkyl, C.sub.8-18 alkenyl or CH.sub.2 --COOH, n=2 to 20, in combination with aliphatic C.sub.8-22 monocarboxylic acids and/or amide-forming aliphatic C.sub.8-22 monocarboxylic acid derivatives) as fabric softeners stable in the presence of electrolytes.
While these and many other proposals are known for improved fabric softening compositions, nevertheless, still further improvements are desired.
One such proposal is described by Schramm, et al. in the commonly assigned, copending application Ser. No. 07/995,102, filed Dec. 22, 1992. According to this proposal stable, aqueous, pourable and water dispersible, fabric softener compositions which include (A) a fabric softening effective amount of an inorganic or organic acid salt of a finely divided softening compound of formula (I): ##STR4## wherein R.sub.1 and R.sub.2, independently, represent C.sub.12 to C.sub.20 alkyl or alkenyl; R.sub.3 represents (CH.sub.2 CH.sub.2 O).sub.p H, CH.sub.3 or H; n and m are each a number of from 1 to 5; and p is a number of from 1 to 10; (B) a dispersant stabilizing effective amount of a dispersant having the formula (II) , (III), (IV) or (V) : ##STR5## wherein
R.sub.4 represents a hydrocarbon group having from 8 to 22 carbon atoms,
R.sub.5 represents a hydrocarbon group having from 1 to 22 carbon atoms,
R.sub.6 represents C.sub.1 -C.sub.4 alkyl or hydroxyalkyl,
R.sub.7 represents C.sub.1 -C.sub.4 alkyl or hydroxyalkyl,
R.sub.8 and R.sub.9 each, independently represent a hydrocarbon group having from 8 to 22 carbon atoms,
R.sub.10 represents a hydrocarbon group having from 8 to 22 carbon atoms,
R.sub.11 represents a hydrocarbon group having from 1 to 22 carbon atoms which may have an hydroxyl group substituent,
R.sub.12 and R.sub.13, independently, represent C.sub.1 -C.sub.4 alkyl or hydroxyalkyl,
Z represents a divalent alkylene group of from 1 to 6 carbon atoms, or an hydroxyl substituted alkylene group;
R.sub.14 represents a hydrocarbon group having from 8 to 22 carbon atoms;
R.sub.15 represents a hydrogen atom or C.sub.1 -C.sub.4 alkyl or hydroxyalkyl; and
(C) an aqueous solvent, were provided as ready-to-use products or as concentrates to be used at reduced levels or which may be diluted with water prior to use at the same or similar levels as the ready-to-use products. In the ready-to-use composition the total amount of amidoamine softener (A) and stabilizing dispersant (B) is generally in the range of from about 2 to 8% by weight. In the concentrated form the total amount of (A) and (B) is generally in the range of from about 12 to 60% and may be diluted at ratios of water:concentrate as high as about 4:1 to even 8:1 or 9:1, and still provide acceptable softening performance, equivalent or better than that achieved using conventional quaternary cationic surfactant softeners, such as dimethyl distearyl ammonium chloride (DMDSAC).
An especially preferred composition according to the prior proposal of Schramm, Jr., et al. (in terms of a ready-to-use formula or dilutable concentrate) includes the following ingredients:
(A) from about 2 to 8% by weight of a salt of bis(hydrogenated tallow amidoethyl)-2-hydroxyethyl amine;
(B) from about 0.2 to 1.5% by weight of a stabilizing dispersant compound selected from dimethyl hydrogenated tallow amine, methyl dihydrogenated tallow amine, N,N'N'-tris(2-hydroxyethyl)-N-tallow-1,3-diaminopropane, and oleic imidazoline;
(C) from about 0.5 to 5% of C.sub.2 H.sub.5 OH, C.sub.3 H.sub.7 OH, or mixture thereof;
(D) 0 to about 2% of C.sub.6 to C.sub.16 fatty alcohol; and
(E) from about 87 to 94% water; the composition having a pH of less than 4.
An alternative embodiment of the Schramm, Jr., et al. fabric softener aqueous liquid compositions which is adaptable for use in the rinse cycle of a laundering process and which is described as stable, pourable, and dispersible in water, includes the following ingredients:
(A') an inorganic or organic acid salt of bis(hydrogenated tallow amidoethyl) hydroxyethyl amine,
(B') an inorganic or organic acid salt of bis(non-hydrogenated tallow amidoethyl) hydroxyethyl amine, with the total amount of (A') and (B') being from about 2% to about 50% by weight of the composition, and the ratio by weight of (A') to (B') being in the range of from about 10:1 to abut 1.5:1, and an aqueous solvent.
While the compositions disclosed in the aforesaid application Ser. No. 07/995,102 of Schramm, Jr., et al. provide highly effective stable and pourable liquid fabric softener compositions, it has been found, in practice, that with concentrations of the amidoamine fabric softening compound, e.g., Varisoft 510, in excess of 11 weight percent, the product viscosity becomes excessively high, even in the presence of electrolytes, e.g., CaCl.sub.2, or solvents, e.g., propanol. While higher total concentrations of the amidoamine were achieved using the soft tallow product Varisoft 512 or mixtures of Varisoft 512 and hard tallow product, Varisoft 510, the softening performance of the Varisoft 512 containing compositions, presumably due to the lack of hydrogen bonding sites on the protonated soft tallow compound, was not sufficiently improved.
European Patent No. 413,249A1, published Feb. 20, 1991, describes a laundry softener composition with improved dispersibility and back wetting ability. In these compositions a fatty acid ester quat, e.g. ##STR6## (R represents linear saturated or unsaturated aliphatic alkyl residue with 16 to 18 carbon atoms) is used in combination with an amine base structure, inclusive of various imidazole compounds, and amido tertiary amine compounds.
Therefore, the present inventors set out to provide ways to increase the concentration in the liquid fabric softening composition of the amidoamine softener compound Varisoft 510 in view of the very good environmental attributes and favorable acute toxicity data of this compound and its strong softening performance. As a result of these efforts many different types and classes of compounds and approaches were tested or considered. Among the classes of compounds tested as viscosity controlling agents in an effort to achieve stable, pourable, liquid compositions based on Varisoft 510 in amounts of 10 to 20% by weight mention can be made of hydrocarbons, e.g., paraffins, organic acids, e.g., citric acid, cationic alumina, cationic polymers and electrolytes, e.g., CaCl.sub.2.
The viscosity of concentrated dispersions of softeners can be controlled by taking one of several suitable measures. For example Mourson and Stewart (U.S. Pat. No. 3,954,634) suggest producing the dispersion as usual by stirring the cationic softener raw material into water and subsequently homogenizing it under a pressure of 16-40 N/mm.sup.2. Concentrations that were achieved by this method were 10-15%. Verbruggen (EP Patent 0013780) was able to prepare stable softener dispersions of low viscosity by the addition of antigelling agents, such as hydrocarbons, aliphatic fatty acids, and fatty acid methyl esters (2-4%). Concentrations of 12-20% were obtained in this way for imidoazoline and di-alkyl-ammonium compounds. The use of hydrocarbon materials such as paraffin oils and paraffin waxes is also claimed in British Patent 1,601,360. Gofbinet (EP 0,000,406) used ethoxylated diamines, such as ethoxylated tallow propylene diamine or alkylpyridine compounds to obtain low viscosity, uniform and stable cationic dispersions up to 15% active ingredients level. In his paper Helmut Hein (Tenside Detergents 18 (1981) 5) refers to the use of ionogenic (organic ammonium compounds, see below) and simple non-ionogenic emulsifiers (such as Nonylphenol 10 Aeo, and Oleylalcohol 8 Aeo) for lowering the viscosity of fabric softener dispersions. ##STR7##
U.S. Pat. No. 4,454,049 describes the use of water miscible organic solvents such as hexylene glycol and nonionic extenders including C.sub.12 -C.sub.24 linear and branched noncyclic hydrocarbons, and esters of glycerol with C.sub.12 -C.sub.24 fatty acids as viscosity controlling agents to prepare concentrated dispersions (at least 20% actives) of substantially water-insoluble cationic imidazolinium compounds. U.S. Pat. No. 4,724,089 discloses the use of the following cyclic amines to prepare highly concentrated dispersions. ##STR8##
James and Ogden (Journal of the American Oil Chemist's Society 56 1979) describe that the viscosity of aqueous cationic dispersions is highly affected by the manufacturing variables such as the temperature of the dispersion, electrolyte content, and method of stirring. Not only the dimension and speed of the stirrer but also the stirring time and the size and construction of the mixing tank influence the fineness of the dispersion. They also point out that dispersions of low viscosity can be produced directly by homogenization.
However, of the many approaches tested by the present inventors, it was found that the incorporation of cyclic imidazolinium compounds not only significantly increased the concentratability of the fatty amido tertiary amine but, quite surprisingly, also significantly improved the softening efficacy of Varisoft 510.
Accordingly, it is an object of this invention to provide low viscosity, stable and flowable aqueous dispersions containing softening effective amount of fatty amido tertiary amine fabric softener.
Another object of the invention is to provide such low viscosity, stable and flowable aqueous with the fatty amido tertiary amine fabric softener in amounts of at least 10 percent by weight of the composition.